This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present invention that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Interactive service mechanism provides synchronization between a video program and an application a user can interact with, in order to provide added or interactive services to the user. Examples of interactive service are voting applications, interactive games, getting information about a product, product ordering. The video program may be live, streamed out from a camera to a broadcaster and ultimately to a terminal, or pre-recorded and streamed from a server to a terminal. It may also be played locally in the terminal from a file. An interactive service may require to be synchronized with a video program. Synchronization information is managed and sent from the network side and retrieved by the terminal. This permits to know when to activate the associated interactive application or part of an interactive application called interactive object.
An interactive object is a piece of software (executable by a processor or interpretable by a virtual machine) as for instance a so called applet or script that uses a Man to Machine Interface to provide the terminal's user the ability to interact with video programs the user is currently watching. In video distribution systems, interactive content is generally transmitted using end-to-end solutions, from the content provider, through the broadcaster up to the terminal. The content provider and the broadcaster sometime form only one entity.
The European patent application 07300769.2 from Thomson Licensing describes the transmission of interactive content under the form of synchronization marks using RTP timestamp.
The insertion of an interactive content is not necessarily performed at the video encoder. The interactive content is then not accurately synchronized to the video content at the output of the video encoder.